libcryptopp: Free C++ class library of cryptographic schemes

Crypto++ Library is a free C++ class library of cryptographic schemes.
Currently the library consists of the following, some of which are other people's code, repackaged into classes.

One purpose of Crypto++ is to act as a repository of public domain (not copyrighted) source code. Although the library is copyrighted as a compilation, the individual files in it (except for a few exceptions listed in the license) are in the public domain.